Use of the Salmonella Dublin ELISA demonstrates varying seroprevalence across age groups at dairy heifer-raising facilities in New York.

Abstract

OBJECTIVE: To investigate the role of dairy heifer-raising facilities as a possible source of exposure to Salmonella Dublin. We hypothesized that heifers near the time of departure to the home farms are more likely to have been exposed to S Dublin in comparison to heifers near the time of arrival at the heifer-raising facility. METHODS: At 5 enrolled heifer raisers, we collected serum samples from animals within 3 different age groups: 3 to 4 months (age group 1), 10 to 12 months (age group 2), and 20 to 22 months (age group 3). All serum samples were tested for S Dublin antibodies using the PrioCHECK S Dublin ELISA kit. RESULTS: Age group 2 had the highest proportion of ELISA-positive animals (35 of 149 [23.5%]), and age group 2 had increased odds of ELISA positivity relative to the other age groups (OR, 3.95; 95% CI, 1.91 to 8.14). Age group 2 also had the highest median ELISA percentage of positivity value (3; range, -14 to 222), with differences between age groups 1 and 2 and groups 1 and 3. CONCLUSIONS: These observations suggest that animals at heifer-raising facilities are likely to be exposed to S Dublin prior to 10 to 12 months of age and are continuously exposed to this serotype at the raising facilities. CLINICAL RELEVANCE: These findings can be used to guide decision-making on the use of off-site heifer-raising facilities and inform the development of targeted management protocols to reduce the risk of S Dublin exposure among animals arriving at these operations.